Your MacBook Pro
goes brighter.

I was watching Silo in a dark room and could barely see what was happening. Turning the brightness all the way up did not help, because the limit macOS hands you is not the limit of the panel.

Apps already do parts of this and I tried the good ones. BrightXDR did not work with protected video from Netflix and Apple TV+ on my setup. BetterDisplay worked, but the features I wanted were behind Pro. BrightIntosh is free if you build it yourself, which meant installing Xcode, and I did not have the disk space. MonitorControl handled my external displays but not the built-in boost, so I was running two apps and still missing a piece.

So I spent two days building the one app that does all of it.

• Brightness past the limit. 0 to 159%. Below 100% it moves the actual backlight. At 100% and above it lights an EDR surface to reach the panel's extra range, roughly 1.59× standard white.
• Protected video still plays. The boost is one pixel in a corner, not a full-screen overlay, so Apple TV+ and Netflix keep playing instead of going black.
• A HUD that stays out of the way. A compact brightness and volume readout under the notch, where nothing was going to happen anyway. Drag it where you like, or keep macOS's own bezel instead.
• Real external monitor control. Brightness, contrast, volume and mute over DDC/CI. Those are the monitor's own hardware settings, not a dark layer painted on top.
• Media keys follow your cursor. Whichever display the pointer is on is the one the keys adjust. Option opens System Settings, Option and Shift together give you quarter steps.
• Dimming below the floor. When a monitor's own minimum is still too bright, gamma takes it the rest of the way down to black.
• Hotkeys and an exclusion list. Bind brightness up and down, max brightness, and display sleep. Name the apps that should drop the boost when they come to the front.
• Nothing else. No ads, no subscription, no analytics, no account, nothing phoning home. The whole thing is in the repo if you want to read it.

There is no download to double-click. You clone the repo and run the build script, which needs Apple's Command Line Tools but not Xcode itself:

git clone https://github.com/kelvintiger/KelvinXDR.git
cd KelvinXDR
./build.sh
cp -R build/KelvinXDR.app /Applications/
open /Applications/KelvinXDR.app

The README is the source of truth if any of that changes. If the app ever quits in a bad state and leaves a display looking wrong, killall KelvinXDR hands every screen back to macOS's own color management.

• Boost is built-in onlyIt needs the XDR panel in the laptop. External displays get DDC brightness, no boost.
• DDC depends on the monitorDocks and HDMI extenders often drop the channel it needs, and then there is nothing to talk to.
• Auto-brightness fights itAutomatic brightness lowers the backlight, and the boost scales down along with it.
• Private APIsIOAVService, DisplayServices and OSDUIHelper are undocumented. Apple can change any of them.

KelvinXDR is GPL-3.0 because it started from BrightXDR's code. The DDC/CI work is ported from MonitorControl, which is MIT. The EDR trigger window and the gamma constants follow BrightIntosh, and a few interface ideas come from BetterDisplay. Full credits and license text are in the repo.

I built it over two days with coding help from Claude Fable 5. The app icon is my cat, who also has a calculator on this site.

• KelvinXDR collects and transmits nothing. The app makes no network requests. Nothing about you, your Mac, or how you use it is sent anywhere, to me or to anyone else.
• Your preferences stay on your Mac. Brightness levels, hotkeys, HUD position, the app exclusion list: all of it is stored locally by the app on your own machine. None of it syncs, uploads, or leaves the device.
• No analytics, no telemetry. There is no usage counter, no crash reporter, no unique identifier, no licence check, no update ping. The app never opens a connection at all.
• This page uses Cloudflare Web Analytics, which is cookieless. It sets no cookies, builds no profile, and cannot follow you to other sites. It counts page views and referrers in aggregate. That is the whole of it.
• Questions. KelvinXDR@kelvinct.com.

• The licence is the GPL, and it is what counts. KelvinXDR is released under GPL-3.0. Your rights to run, study, modify and redistribute it come from that licence. Nothing on this page adds any restriction to the software, and if anything here appears to conflict with GPL-3.0, GPL-3.0 controls.
• No warranty. The software is provided as is, without warranty of any kind, express or implied, as stated in sections 15 and 16 of GPL-3.0. You run it at your own risk, and it is doing unusual things to your display.
• It can stop working. KelvinXDR relies on private, undocumented Apple APIs. A macOS update can change or remove them at any time, and the app may then break, misbehave, or need changes to work again. There is no support obligation and no commitment to keep it running.
• Not affiliated with Apple. This is an independent project with no affiliation with, endorsement by, or sponsorship from Apple Inc. Apple, Mac, MacBook Pro, macOS and XDR are trademarks of Apple Inc.
• Security reports. If you find something exploitable, report it privately through the security policy rather than a public issue. It sets out what is in scope, what is already known and documented, and what to expect: best effort, no SLA, and you are free to disclose publicly if a report goes unanswered.
• Scope. These terms cover this page and the instructions on it. They are not a licence for the software and do not replace one: the licence lives in the repo.